Feedback photoplethysmography measuring device and measuring method thereof

Abstract

A feedback photoplethysmography measuring device is provided, including: a measuring device that measures a human body to obtain a photoplethysmography signal; an analog/digital conversion unit that converts the photoplethysmography signal measured by the measuring device to a photoplethysmography value which is a digital value; a variation-degree calculation unit that calculates a photoplethysmography variation value according to the photoplethysmography value converted by the analog/digital conversion unit; and a feedback emitted light amplitude adjustment unit that controls the measuring device according to a plurality of preset control values or the adjusted photoplethysmography variation value calculated by the variation-degree calculation unit, and adjusts the photoplethysmography variation value to a minimum variation value.

What is claimed is: 
     
         1 . A feedback photoplethysmography measuring device, comprising:
 a measuring device, comprising:   a light emitter that emits light with a particular wavelength to a human body; and   a light receiver that receives the light with a particular wavelength transmitted through the human body or reflected by the human body, and converts the light to a photoplethysmography signal which is an electrical signal;   an analog/digital conversion unit that converts the photoplethysmography signal converted by the light receiver which is an analog signal to a photoplethysmography value which is a digital value;   a variation-degree calculation unit that calculates a photoplethysmography variation value according to the photoplethysmography value converted by the analog/digital conversion unit; and   a feedback emitted light amplitude adjustment unit that controls brightness of the light emitted by the light emitter according to a plurality of preset control values or the adjusted photoplethysmography variation value calculated by the variation-degree calculation unit, and adjusts the photoplethysmography variation value to a minimum variation value, to control the brightness of the light emitted by the light emitter to be optimal.   
     
     
         2 . The feedback photoplethysmography measuring device according to  claim 1 , further comprising: a light emission sequence control unit that sends an emitted light sequence signal to the light emitter through phase, pulse or sine-wave control, to control time and frequency of the light emitted by the light emitter. 
     
     
         3 . The feedback photoplethysmography measuring device according to  claim 1 , further comprising: a signal processing unit that calculates a heart rate value with the photoplethysmography value when the photoplethysmography variation value is the minimum variation value. 
     
     
         4 . The feedback photoplethysmography measuring device according to  claim 3 , wherein the heart rate value=60/time difference (heart rate/minute), and the time difference is a time length between adjacent crests in the photoplethysmography value. 
     
     
         5 . The feedback photoplethysmography measuring device according to  claim 1 , wherein the light emitted by the light emitter is one of green light with a wavelength of 495 nm to 570 nm, red light with a wavelength of 620 nm to 750 nm and infrared light with a wavelength of 780 nm to 1000 nm. 
     
     
         6 . The feedback photoplethysmography measuring device according to  claim 1 , wherein the photoplethysmography variation value is 
       
         
           
             
               
                 Var 
                 = 
                 
                   
                     1 
                     N 
                   
                    
                   
                     [ 
                     
                       
                         ∑ 
                         
                           n 
                           = 
                           1 
                         
                         N 
                       
                        
                       
                           
                       
                        
                       
                         
                           ( 
                           
                             
                               I 
                                
                               
                                 [ 
                                 n 
                                 ] 
                               
                             
                             - 
                             M 
                           
                           ) 
                         
                         2 
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein N is the total data number of the photoplethysmography value through sequence analysis or Fourier transform, I[n] is the corresponding light intensity of the photoplethysmography value via sequence analysis or Fourier transform at the time n, and M is an average value of I[n]. 
     
     
         7 . The feedback photoplethysmography measuring device according to  claim 1 , wherein the feedback emitted light amplitude adjustment unit controls the brightness of the light emitted by the light emitter with each of the control values, and judges that the minimum one in the photoplethysmography variation value of each of the corresponding control values calculated by the variation-degree calculation unit as the minimum variation value. 
     
     
         8 . The feedback photoplethysmography measuring device according to  claim 1 , wherein, when the feedback emitted light amplitude adjustment unit judges that the current photoplethysmography variation value calculated by the variation-degree calculation unit is less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to increase, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, wherein, when the current photoplethysmography variation value calculated by the variation-degree calculation unit is judged to be less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the previous photoplethysmography variation value is the minimum variation value. 
     
     
         9 . A feedback photoplethysmography measuring device, comprising:
 a measuring device, comprising:   a plurality of light emitters that emit light with a particular wavelength but in different sequences to a human body respectively; and   a light receiver that receives the light with a particular wavelength but in different sequences transmitted through the human body or reflected by the human body, and converts the light to a plurality of photoplethysmography signals which are electrical signals;   a light emission sequence control unit that sends each of a plurality of emitted light sequence signals to each of the light emitters through phase, pulse or sine-wave control, to control time and frequency of the light emitted by each of the light emitters;   an analog/digital conversion unit that converts the photoplethysmography signals converted by the light receiver which are analog signals to a photoplethysmography value which is a digital value respectively;   a variation-degree calculation unit that calculates a plurality of photoplethysmography variation values according to the photoplethysmography values converted by the analog/digital conversion unit; and   a feedback emitted light amplitude adjustment unit that controls brightness of the light emitted by each of the light emitters according to a plurality of preset control values or the adjusted photoplethysmography variation values calculated by the variation-degree calculation unit, and adjusts at least one of the photoplethysmography variation values to a minimum variation value, to control the brightness of the light emitted by the light emitter corresponding to the minimum variation value to be optimal.   
     
     
         10 . The feedback photoplethysmography measuring device according to  claim 9 , further comprising: a signal processing unit that calculates a heart rate value for the photoplethysmography value which is the minimum variation value when one of the photoplethysmography variation values is the minimum variation value. 
     
     
         11 . The feedback photoplethysmography measuring device according to  claim 10 , wherein the heart rate value=60/time difference (heart rate/minute), and the time difference is a time length between adjacent crests in the photoplethysmography value which is the minimum variation value. 
     
     
         12 . The feedback photoplethysmography measuring device according to  claim 9 , further comprising: a signal processing unit calculates that, when one of the photoplethysmography variation values of which the wavelength is red light and one of the photoplethysmography variation values of which the wavelength is infrared light are both the minimum variation value, a ratio R for the photoplethysmography variation value of which the wavelength of the minimum variation value is red light and the photoplethysmography variation value of which the wavelength is infrared light, and obtains a blood oxygen concentration value by looking up a table. 
     
     
         13 . The feedback photoplethysmography measuring device according to  claim 12 , wherein the ratio is 
       
         
           
             
               
                 R 
                 = 
                 
                   
                     [ 
                     
                       
                         ( 
                         
                           
                             S 
                             R_max 
                           
                           - 
                           
                             S 
                             R_min 
                           
                         
                         ) 
                       
                       
                         S 
                         
                           R 
                           _mean 
                         
                       
                     
                     ] 
                   
                   / 
                   
                     [ 
                     
                       
                         
                           S 
                           
                             I 
                              
                             R_max 
                           
                         
                         - 
                         
                           S 
                           
                             I 
                              
                             R_min 
                           
                         
                       
                       
                         S 
                         
                           
                             I 
                              
                             R 
                           
                           _mean 
                         
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein S R   _   max  is the crest value in the photoplethysmography variation value of which the corresponding minimum variation value is red light, S R   _   min  is the trough value in the photoplethysmography variation value of which the corresponding minimum variation value is red light, S R   _   mean =(S R   _   max +S R   _   min )/2, S IR   _   max  is the crest value in the photoplethysmography variation value of which the corresponding minimum variation value is infrared light, S IR   _   min  is the trough value in the photoplethysmography variation value of which the corresponding minimum variation value is infrared light, and S IR   _   mean =(S IR   _   max +S IR   _   min )/2. 
     
     
         14 . The feedback photoplethysmography measuring device according to  claim 9 , wherein the light emitted by the light emitters is one green light with a wavelength of 495 nm to 570 nm, red light with a wavelength of 620 nm to 750 nm and infrared light with a wavelength of 780 nm to 1000 nm. 
     
     
         15 . The feedback photoplethysmography measuring device according to  claim 9 , wherein each of the photoplethysmography variation values is 
       
         
           
             
               
                 Var 
                 = 
                 
                   
                     1 
                     N 
                   
                    
                   
                     [ 
                     
                       
                         ∑ 
                         
                           n 
                           = 
                           1 
                         
                         N 
                       
                        
                       
                           
                       
                        
                       
                         
                           ( 
                           
                             
                               I 
                                
                               
                                 [ 
                                 n 
                                 ] 
                               
                             
                             - 
                             M 
                           
                           ) 
                         
                         2 
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein N is the total data number of each of the photoplethysmography values through sequence analysis or Fourier transform, I[n] is the corresponding light intensity of each of the photoplethysmography values via sequence analysis or Fourier transform at the time n, and M is an average value of I[n]. 
     
     
         16 . The feedback photoplethysmography measuring device according to  claim 9 , wherein the feedback emitted light amplitude adjustment unit controls the brightness of the light emitted by the light emitter with each of the control values, and judges that the minimum one in the photoplethysmography variation value of each of the corresponding control values calculated by the variation-degree calculation unit as the minimum variation value. 
     
     
         17 . The feedback photoplethysmography measuring device according to  claim 9 , wherein, when the feedback emitted light amplitude adjustment unit judges that the current photoplethysmography variation value calculated by the variation-degree calculation unit is less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to increase, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, wherein, when the current photoplethysmography variation value calculated by the variation-degree calculation unit is judged to be less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the previous photoplethysmography variation value is the minimum variation value. 
     
     
         18 . A measuring method of a feedback photoplethysmography measuring device, comprising:
 emitting, by a light emitter, light with a particular wavelength to a human body;   receiving, by a light receiver, the light with a particular wavelength transmitted through the human body or reflected by the human body, and converting the light to a photoplethysmography signal which is an electrical signal;   converting, by an analog/digital conversion unit, the photoplethysmography signal converted by the light receiver which is an analog signal to a photoplethysmography value which is a digital value;   calculating, by a variation-degree calculation unit, a photoplethysmography variation value according to the photoplethysmography value converted by the analog/digital conversion unit; and   adjusting, by a feedback emitted light amplitude adjustment unit, the photoplethysmography variation value, and controlling brightness of the light emitted by the light emitter according to a plurality of preset control values or the adjusted photoplethysmography variation value calculated by the variation-degree calculation unit;   wherein the feedback emitted light amplitude adjustment unit judges whether the adjusted photoplethysmography variation value is the minimum variation value.   
     
     
         19 . The measuring method according to  claim 18 , wherein, in the step of controlling, by the feedback emitted light amplitude adjustment unit, brightness of the light emitted by the light emitter, a light emission sequence control unit that sends an emitted light sequence signal to the light emitter through phase, pulse or sine-wave control, to control time and frequency of the light emitted by the light emitter. 
     
     
         20 . The measuring method according to  claim 18 , after the step of judging, by the feedback emitted light amplitude adjustment unit, the adjusted photoplethysmography variation value to be the minimum variation value, further comprising: calculating, by a signal processing unit, a heart rate value with the photoplethysmography value when the photoplethysmography variation value is the minimum variation value. 
     
     
         21 . The measuring method according to  claim 20 , wherein the heart rate value=60/time difference (heart rate/minute), and the time difference is a time length between adjacent crests in the photoplethysmography value. 
     
     
         22 . The measuring method according to  claim 18 , wherein the light emitted by the light emitter is one of green light with a wavelength of 495 nm to 570 nm, red light with a wavelength of 620 nm to 750 nm and infrared light with a wavelength of 780 nm to 1000 nm. 
     
     
         23 . The measuring method according to  claim 18 , wherein the photoplethysmography variation value is 
       
         
           
             
               
                 Var 
                 = 
                 
                   
                     1 
                     N 
                   
                    
                   
                     [ 
                     
                       
                         ∑ 
                         
                           n 
                           = 
                           1 
                         
                         N 
                       
                        
                       
                           
                       
                        
                       
                         
                           ( 
                           
                             
                               I 
                                
                               
                                 [ 
                                 n 
                                 ] 
                               
                             
                             - 
                             M 
                           
                           ) 
                         
                         2 
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein N is the total data number of the photoplethysmography value through sequence analysis or Fourier transform, I[n] is the corresponding light intensity of the photoplethysmography value via sequence analysis or Fourier transform at the time n, and M is an average value of I[n]. 
     
     
         24 . The measuring method according to  claim 18 , wherein the feedback emitted light amplitude adjustment unit controls the brightness of the light emitted by the light emitter with each of the control values, and judges that the minimum one in the photoplethysmography variation value of each of the corresponding control values calculated by the variation-degree calculation unit as the minimum variation value. 
     
     
         25 . The measuring method according to  claim 18 , wherein, when the feedback emitted light amplitude adjustment unit judges that the current photoplethysmography variation value calculated by the variation-degree calculation unit is less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to increase, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, wherein, when the current photoplethysmography variation value calculated by the variation-degree calculation unit is judged to be less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the previous photoplethysmography variation value is the minimum variation value. 
     
     
         26 . A measuring method of a feedback photoplethysmography measuring device, comprising:
 emitting, by a plurality of light emitters, light with a particular wavelength but in different sequences to a human body;   receiving, by a light receiver, the light with a particular wavelength but in different sequences transmitted through the human body or reflected by the human body, and converting the light to a plurality of photoplethysmography signals which are electrical signals;   sending, by a light emission sequence control unit, each of a plurality of emitted light sequence signals to each of the light emitters through phase, pulse or sine-wave control, to control time and frequency of the light emitted by each of the light emitters;   converting, by an analog/digital conversion unit, the photoplethysmography signals converted by the light receiver which are analog signals to a plurality of a photoplethysmography value which is a digital value;   calculating, by a variation-degree calculation unit, a plurality of photoplethysmography variation values according to the photoplethysmography values converted by the analog/digital conversion unit; and   adjusting, by a feedback emitted light amplitude adjustment unit, the photoplethysmography variation values, and controlling brightness of the light emitted by each of the light emitters according to a plurality of preset control values or the adjusted photoplethysmography variation values calculated by the variation-degree calculation unit respectively;   wherein the feedback emitted light amplitude adjustment unit judges whether at least one of the adjusted photoplethysmography variation values is the minimum variation value.   
     
     
         27 . The measuring method according to  claim 26 , after the step of judging, by the feedback emitted light amplitude adjustment unit, at least one of the adjusted photoplethysmography variation values to be the minimum variation value, further comprising: calculating, by a signal processing unit, a heart rate value for the photoplethysmography value which is the minimum variation value when at least one of the photoplethysmography variation values is the minimum variation value. 
     
     
         28 . The measuring method according to  claim 27 , wherein the heart rate value=60/time difference (heart rate/minute), and the time difference is a time length between adjacent crests in the photoplethysmography value which is the minimum variation value. 
     
     
         29 . The measuring method according to  claim 26 , after the step of judging, by the feedback emitted light amplitude adjustment unit, at least one of the adjusted photoplethysmography variation values to be the minimum variation value, further comprising: calculating, by a signal processing unit, when one of the photoplethysmography variation values of which the wavelength is red light and one of the photoplethysmography variation values of which the wavelength is infrared light are both the minimum variation value, a ratio R for the photoplethysmography variation value of which the wavelength of the minimum variation value is red light and the photoplethysmography variation value of which the wavelength is infrared light, and obtaining a blood oxygen concentration value by looking up a table. 
     
     
         30 . The measuring method according to  claim 29 , wherein the ratio is 
       
         
           
             
               
                 R 
                 = 
                 
                   
                     [ 
                     
                       
                         ( 
                         
                           
                             S 
                             R_max 
                           
                           - 
                           
                             S 
                             R_min 
                           
                         
                         ) 
                       
                       
                         S 
                         
                           R 
                           _mean 
                         
                       
                     
                     ] 
                   
                   / 
                   
                     [ 
                     
                       
                         
                           S 
                           
                             I 
                              
                             R_max 
                           
                         
                         - 
                         
                           S 
                           
                             I 
                              
                             R_min 
                           
                         
                       
                       
                         S 
                         
                           
                             I 
                              
                             R 
                           
                           _mean 
                         
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein S R   _   max  is the crest value in the photoplethysmography variation value of which the corresponding minimum variation value is red light, S R   _   min  is the trough value in the photoplethysmography variation value of which the corresponding minimum variation value is red light, S R   _   mean =(S R   _   max +S R   _   min )/2, S IR   _   max  is the crest value in the photoplethysmography variation value of which the corresponding minimum variation value is infrared light, S IR   _   min  is the trough value in the photoplethysmography variation value of which the corresponding minimum variation value is infrared light, and S IR   _   mean =(S IR   _   max +S IR   _   min )/2. 
     
     
         31 . The measuring method according to  claim 30 , wherein the light emitted by the light emitters is one green light with a wavelength of 495 nm to 570 nm, red light with a wavelength of 620 nm to 750 nm and infrared light with a wavelength of 780 nm to 1000 nm. 
     
     
         32 . The measuring method according to  claim 26 , wherein each of the photoplethysmography variation values is 
       
         
           
             
               
                 Var 
                 = 
                 
                   
                     1 
                     N 
                   
                    
                   
                     [ 
                     
                       
                         ∑ 
                         
                           n 
                           = 
                           1 
                         
                         N 
                       
                        
                       
                           
                       
                        
                       
                         
                           ( 
                           
                             
                               I 
                                
                               
                                 [ 
                                 n 
                                 ] 
                               
                             
                             - 
                             M 
                           
                           ) 
                         
                         2 
                       
                     
                     ] 
                   
                 
               
               , 
             
           
         
       
       wherein N is the total data number of each of the photoplethysmography values through sequence analysis or Fourier transform, I[n] is the corresponding light intensity of each of the photoplethysmography values via sequence analysis or Fourier transform at the time n, and M is an average value of I[n]. 
     
     
         33 . The measuring method according to  claim 26 , wherein the feedback emitted light amplitude adjustment unit controls the brightness of the light emitted by the light emitter with each of the control values, and judges that the minimum one in the photoplethysmography variation value of each of the corresponding control values calculated by the variation-degree calculation unit as the minimum variation value. 
     
     
         34 . The measuring method according to  claim 26 , wherein, when the feedback emitted light amplitude adjustment unit judges that the current photoplethysmography variation value calculated by the variation-degree calculation unit is less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to increase, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, wherein, when the current photoplethysmography variation value calculated by the variation-degree calculation unit is judged to be less than the previous photoplethysmography variation value, the feedback emitted light amplitude adjustment unit adjusts the current photoplethysmography variation value to control the brightness of the light emitted by the light emitter to decrease, and when the current photoplethysmography variation value calculated by the variation-degree calculation unit is greater than the previous photoplethysmography variation value, the previous photoplethysmography variation value is the minimum variation value.